The invention is based on a priority application EP05291927.1 which is hereby incorporated by reference.
The invention relates to a method for network analysis in an access network in connection with a data transmission network, in particular an xDSL network, with a plurality of subscriber lines, the method comprising the step of collecting data on physical layer operational parameters of at least one subscriber line.
The invention also relates to a network analyser module for an access network in connection with a data transmission network, in particular an xDSL network, with a plurality of subscriber lines, the network analyser module comprising means for collecting data on physical layer operational parameters of at least one subscriber line.
Additionally, the invention relates to an xDSL network analyser, an integrated circuit, and an access multiplexer linecard comprising an inventive network analyser module, as well as to a computer program product for network analysis being operable to translate the inventive method into practise.
Due to the fast introduction and spreading of broadband technologies as well as in response to increased competitive pressure and consumer demands, a great number of new applications in the field of rich media services, e.g. delivery of video, VoIP (voice over IP), or gaming, are being developed. Other services of this kind are referred to as triple-play services (voice, video, and data), and require stable high-quality broadband connections—in addition to an overall increased bandwidth—for effective and reliable service delivery over data transmission (or communications) networks, such as a DSL and ADSL networks. In this context, the performance of a communication system is usually expressed in terms of QoS (Quality of Service). Depending upon the communication system in question, QoS may relate to service performance, SNR (Signal to Noise Ratio), BER (Bit Error Ratio), throughput rate, reliability, priority, delay, packet loss, number of visual disturbances per hour and other factors specific to each service. QoS is of particular concern for the continuous transmission of the above-mentioned high-bandwidth video and multimedia information, and can be measured in terms of an average delay, losses of transmission units (bits, cells, frames, or packets), or a transmission error rate, for instance. However, the network operators generally do not know if a newly developed application will run on their network (core and access) with the recommended QoS values. Furthermore, it is generally not possible for them to determine the error rate at the level of the application, e.g. video, VoIP, gaming, etc.
DLM (Dynamic Line Management) is a known prior art approach which is aimed at maximising data rates and maintaining quality and stability in communications networks (cf. ALCATEL Technology White Paper “Dynamic Line Management for Digital Subscriber Lines”). DLM allows switching of user/service profiles based on physical layer measurements of the MTBE (Mean Time Between Error Events) or MTBR (Mean Time Between (spontaneous) Resynchronisations). To this end, operational data is collected in order to determine physical line conditions during operation of the network in a non-stationary noise environment. Lines that are identified as stable are then assigned profiles with the highest bit rates possible, based on the physical quality of the line. In accordance with the measurement of physical layer operational parameters, a DLM module will switch a given line to a different profile in an attempt to offer a higher bit rate, ensure improved quality and stability, or reduce crosstalk owing to reduced transmit PSD (Power Spectral Density).
However, as only physical layer parameters are considered DLM does not provide a solution to the above-mentioned issue concerning the QoS requirements per type of application, e.g. delay, errors, etc.